Numerical investigation of Al2O3/water nanofluid laminar convective heat transfer through triangular ducts

In this article, laminar flow-forced convective heat transfer of Al2O3/water nanofluid in a triangular duct under constant wall temperature condition is investigated numerically. In this investigation, the effects of parameters, such as nanoparticles diameter, concentration, and Reynolds number on the enhancement of nanofluids heat transfer is studied. Besides, the comparison between nanofluid and pure fluid heat transfer is achieved in this article. Sometimes, because of pressure drop limitations, the need for non-circular ducts arises in many heat transfer applications. The low heat transfer rate of non-circular ducts is one the limitations of these systems, and utilization of nanofluid instead of pure fluid because of its potential to increase heat transfer of system can compensate this problem. In this article, for considering the presence of nanoparticl: es, the dispersion model is used. Numerical results represent an enhancement of heat transfer of fluid associated with changing to the suspension of nanometer-sized particles in the triangular duct. The results of the present model indicate that the nanofluid Nusselt number increases with increasing concentration of nanoparticles and decreasing diameter. Also, the enhancement of the fluid heat transfer becomes better at high Re in laminar flow with the addition of nanoparticles

Interaction of 3-(1H-tetrazol-5-yl) Coumarin With Bovine Serum Albumin and Calf Thymus DNA: Deciphering the Mode of Binding by In Vitro Studies

Background: Coumarins comprise a large family of heterocyclic compounds with a benzo-a-pyrone moiety. Objectives: This study aimed to analyze the binding affinity of 3-(1H-tetrazol-5-yl) coumarin to bovine serum albumin (BSA) and calf thymus DNA (Ct-DNA) using fluorescence spectroscopy. The quenching of fluorescence was recognized during the interaction between 3-(1H-tetrazol-5-yl) coumarin and BSA, followed by a static mechanism. Methods: The hydrogen bonds, hydrophobic interactions, and Vander Waals forces were regarded as the principal part in the 3-(1H-tetrazol-5-yl) coumarin and BSA complexation process. The fluorescence spectral characteristics demonstrated an enhancement in fluorescence intensity of the 3-(1H-tetrazol-5-yl) coumarin in the presence of ct-DNA solution. Results: The experimental results indicated that the 3-(1H-tetrazol-5-yl) coumarin binds to DNA via interjection, hydrogen bonds, and Vander Waals forces. This work illustrated that BSA fluorescence was quenched by 3-(1H-tetrazol-5-yl) coumarin via a static mechanism and the ct-DNA fluorescence enhancement by 3-(1H-tetrazol-5-yl) coumarin was a static process. The secondary structure of proteins changed upon drug binding. Conclusion: It is deduced that 3-(1H-tetrazol-5-yl) coumarin represents a higher binding affinity to DNA compared to BSA. This finding can be useful in designing more effective new drugs with fewer side effects

Exogenous Nitric Oxide Up-regulates the Runx2 Via Bmp7 Overexpression to Increase the Osteoblast Matrix Production In Vitro

Background: Nitric oxide (NO) is a signaling molecule that is required for the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). According to previous reports, high concentrations of sodium nitroprusside (SNP) inhibit the osteogenic differentiation of BMSCs, while its low concentration promotes this process. Objectives: The present investigation focused on evaluating the underlying mechanism of the osteogenic differentiation of BMSCs treated with low concentrations of SNP as an NO generating agent. Methods: The BMSCs after the 3rd passage was differentiated to osteoblasts when treated with 100 μM for 1 hour every 48 hours until 5, 10, 15, and 20 days of incubation. Then, the matrix production was estimated by quantitative alizarin red assay and calcium determination. The expression of different genes involved in osteogenic differentiation was statistically determined using the reverse transcriptase polymerase chain reaction. Finally, alkaline phosphatase activity was measured by a commercial kit. Results: The exogenous NO caused a significant (P < 0.05) increase in the matrix production of differentiated BMSCs from day 5 to 20. The results showed the elevation of alkaline phosphatase activity and the up-regulation of its gene. Eventually, an increase was observed in the expression of a cascade of other genes such as osteonectin, Bmp7, Smad1, Runx2, and Raf1 in treated BMSCs. Conclusion: Overall, short-time treatment with a low concentration of exogenous NO increases the matrix production via gene up-regulation and protein production, which might open a new window in treating the low-density bone complication

The Impact of Effective Governance and Regulatory Quality on Financial Development Under Economic Conditions of the Mena Countries

The present study uses the Systematic Generalized Method of Moment's (SGMM) model to investigate the effects of effective governance and regulatory quality on financial development in the economic conditions of the Mena countries during the period 2002-2009. The results of the study show a positive relationship between the role or rule of law (RL) and economic growth (GDP) with financial development (FD). The variables of regulatory quality (RO), government budget deficit (BD), government effectiveness (GE) and financial crisis (FC) are negative. The negative sign of regulatory quality, government effectiveness and budget deficit for the MENA countries can be justified as follows; The more accountable and efficient the government in a country, the greater the political stability, the lower the additional regulations and costs, the more extensive the rule of law, the smaller the government effectiveness, and the more restricted the corruption, the greater the financial development requiring the more attention of government and authorities in accountability, compliance of rules and regulatory quality. Also the positive variable of the dependent variable lag; the financial development Index shows the countries' attention to the financial development issue and the use of strategies and infrastructure to increase financial development based on financial liberalization indicators over time, which requires much attention from government authorities

Cytotoxic Effects of Hydroxy Coumarin Derivatives on Mouse Neuroblastoma N2a Cell Line: Effects of Hydroxy Coumarin Derivations in N2A cell line

Neuroblastoma is one of the nervous system cancers, which approximately consists of 9% of childhood cancers. In this study, we evaluated the toxic effects of prenyl hydroxy coumarin derivatives on apoptosis of the neuroblastoma cell line N2A. N2A cells were cultured in DMEM medium, then the effects of different concentrations (0.75–200 μg/mL) of prenyl hydroxy coumarin derivatives during 24, 48, and 72 h were studied. Cell viability was quantified by MTT assay; apoptotic cells were determined using PI staining of DNA fragmentation through flow cytometry (sub-G1 peak). The toxic effect of 3- farnesyl oxi coumarin in the N2A cell starts at 6.25 μg/ml and increases relatively depending on rising in concentration and over time. The toxicity and apoptosis of 3- farnesyl and 6- farnesyl oxi coumarin is more than 3- Geranyl and 6-Geranyl oxi coumarin. Prenyl hydroxy coumarin induces peak sub-G1 in flow cytometry compared to the control group, indicating that induced toxicity, which is involved in apoptotic cell death. Different concentrations of derivatives (0.75-200 μg/mL) in lymphocytes did not induce any anti-proliferative effect in 24 h. In conclusion, prenyl hydroxy coumarin derivatives induce apoptotic effects in the N2A cell line. Then prenyl hydroxy coumarin derivatives sound to be chemotherapeutic agents for the neuroblastoma cancer cells

Numerical investigation of Al₂O₃/water nanofluid laminar convective heat transfer through triangular ducts

<p>Abstract</p> <p>In this article, laminar flow-forced convective heat transfer of Al₂O₃/water nanofluid in a triangular duct under constant wall temperature condition is investigated numerically. In this investigation, the effects of parameters, such as nanoparticles diameter, concentration, and Reynolds number on the enhancement of nanofluids heat transfer is studied. Besides, the comparison between nanofluid and pure fluid heat transfer is achieved in this article. Sometimes, because of pressure drop limitations, the need for non-circular ducts arises in many heat transfer applications. The low heat transfer rate of non-circular ducts is one the limitations of these systems, and utilization of nanofluid instead of pure fluid because of its potential to increase heat transfer of system can compensate this problem. In this article, for considering the presence of nanoparticl: es, the dispersion model is used. Numerical results represent an enhancement of heat transfer of fluid associated with changing to the suspension of nanometer-sized particles in the triangular duct. The results of the present model indicate that the nanofluid Nusselt number increases with increasing concentration of nanoparticles and decreasing diameter. Also, the enhancement of the fluid heat transfer becomes better at high Re in laminar flow with the addition of nanoparticles.</p

The correlation between p16 expression and INK4a locus mutation with grades and stages in oral squamous cell carcinoma

Objective: p16INK4a is a tumor suppressor gene playing a critical role. Researches have indicated the gene to be altered in oral squamous cell carcinoma. Present studies have tried to assess the correlation between p16INK4a expression and INK4a locus mutation in relation to grades and stages of this tumor. Materials and Methods: Expression of p16INK4a was studied immunohistochemically in 58 oral squamous sell carcinoma samples and INK4a locus mutation was determined by polymerase chain reaction (PCR) and conformation sensitive gel electrophoresis (CSGE). Results: Expression of p16INK4a was higher in stage1 compared to stage 2, 3, and 4 (P = 0.234). The difference was not significant in grade 1, 2, and 3 (P = 0.671). The average values of total score (TS) were significantly higher in stage1 compared to stage 2, 3, and 4 (P = 0.035). The average values of complete score (CS) were higher in stage 1 compared to stage 2, 3, and 4 (P = 0.061). The research did not show a significant correlation between lymph node involvement and p16INK4a expression (P = 0.491). It seems that 5.1% (3/58) of samples have mutation in INK4a locus. Conclusion: Loss of p16INK4a expression occurred in initial stages of oral squamous cell carcinoma. Evaluation of TS and CS for p16INK4a might be a useful clinical indicator concerning the tumor. However, gene mutation is believed to have minor rate of genetic alteration in carcinogenesis

Performance Evaluation of Moving-bed Sequencing Batch Reactor for Livestock Wastewater Treatment by SND Process

In this study, the performance of moving-bed sequencing batch reactor with intermittent aeration strategy (IA-MBSBR) was evaluated for treatment of livestock wastewater in simultaneous nitrification-denitrification process. The statistical design and analysis were employed to optimize independent variables such as sludge retention time (SRT), temperature, and aeration rate using response surface methodology (RSM) through Box-Behnken design (BBD). The effect of variables was investigated on chemical oxygen demand (COD) removal and SND efficiency . The analysis of variance (ANOVA) was conducted to confirm the suitability and significance of the quadratic models. Based on the results, a very high regression coefficient was achieved between the variables and the responses: COD removal and SND efficiency were R2 = 0.9788 and R2 = 0.9600, respectively indicating an excellent evaluation of experimental data by polynomial regression model. Long SRT reduced the negative effect of low temperature, but lowered COD removal and ESNDin high temperature. Further, appropriate aeration rate was vital for the SND to reach equilibrium between the nitrification and denitrification processes. The optimal conditions obtained from the models were SRT= 20 d, temperature = 19.16 °C and aeration rate= 0.1 , which results in COD removal and ESND of 92.9 and 91.3%, respectively. It was found that an alternating anaerobic/aerobic conditions with step-filling mode is an effective, economic, and environmentally-friendly strategy for the biological treatment of livestock wastewater in the moving-bed sequencing batch reactor

Study of Crocin &amp; Radiotherapy-induced Cytotoxicity and Apoptosis in the Head and Neck Cancer (HN-5) Cell Line

Abstract Malignant tumors of head and neck carcinomas are the sixth most common type of cancer. Current systemic therapies for cancer show side effects in normal tissues and short-term efficacy due to drug resistance. Consequently, there is much interest in identifying new drugs for cancer treatment. Crocin (an active ingredient of saffron) has been shown to have cytotoxic effects on cancer cell lines. Chemo radiotherapy is the standard treatment for head and neck cancer. In the present study, the cytotoxic effects, inducing apoptosis and the radiation sensitivity of crocin were evaluated in the head and neck cancer cell line (HN-5). HN-5 cells were cultured in a DMEM medium and incubated with different concentrations of crocin (12.5-1000 µg/mL). They were exposed to 2 Gy γ-rays. Cell viability was quantified by the MTT assay. Apoptotic cells were determined using PI staining of DNA fragmentation by flowcytometry (sub-G1 peak). Crocin decreased cell viability in HN-5 cells in a time and concentration dependent manner. Crocin also induced a sub-G1 peak in the flowcytometery histogram of treated cells compared with the control, suggesting that apoptotic cell death is caused by its toxicity. Crocin was also shown to sensitize cells to radiation-induced toxicity and apoptosis. The simultaneous use of crocin and radiation therefore increases radiation sensitivity and cell death. Thus, after further study crocin can be considered as a potential drug and sensitizer in cancer treatment